Triamino pyrimidine N-oxides are known in the art. U.S. Pat. No. 3,461,461 specifically discloses and claims certain 6-amino-4-(substituted amino)-1,2-dihydro-1-hydroxy-2-iminopyrimidines. These compounds have various utilities, according to U.S. Pat. No. 3,461,461 such as forming salts with mothproofing agents, aiding in the formation of pickling inhibitors, and pharmaceutical uses, particularly antihypertensive effects.
A new method of preparing the compounds of U.S. Pat. No. 3,461,461 is disclosed in U.S. Ser. No. 464,476, filed Apr. 26, 1974, now U.S. Pat. No. 3,910,928. This method involves the preparation of a novel 2-R.sub.3 -3-(cyanoimino)-3-(amino)propionitrile of the formula ##STR5##
This 3-(cyanoimino)propionitrile is reacted with a hydroxylamine salt and base thereby forming the 6-amino-5-optionally-substituted-2,4-diaminopyrimidine-3-oxide of the formula ##STR6## R.sub.1, R.sub.2, and R.sub.3 having the same values as in Ser. No. 464,476, now U.S. Pat. No. 3,910,928.
The necessary disclosure for the preparation of the compounds of formulas I and II from Ser. No. 464,476, now U.S. Pat. No. 3,910,928, is incorporated within this disclosure by reference.
A new method has been devised for synthesizing the 3-(cyanoimino)propionitrile of Formula I. This method involves the preparation of a N,2-dicyanoacetimidate as per the methods of Hirayama, et al., Heterocycles, 2, 461 (1974) and Japanese Patent Application J49080-021 of Daichi Seiyaku Company, followed by nucleophilic substitution to prepare the 3-(cyanoimino)propionitrile of Formula I.